DAZZLE: “Smash” gals Katharine McPhee (left) and Megan Hilty sparkle on the new show about Broadway. (Mark Seliger/NBC)

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Several years ago I got a call from the BBC asking if I’d be a judge on a new reality show. They had no idea who I was, but they were looking for a mean Broadway critic and when they Googled “mean Broadway critic,” my name came up.

The show, which was being shot in Los Angeles and was to air in the United States on ABC, was about ballroom dancing.

It sounded like fun, so I was game. Until I got the contract. It was onerous. And the pay was peanuts — only a few thousand bucks for four episodes. I said no.

That decision has haunted me for seven years — I shudder, in fact, as I write this — because the show turned out to be “Dancing with the Stars,” which regularly draws 20 million viewers. I’ve never been one of them. I don’t have the stomach to watch it, especially when I learned the judges now make close to $100,000 an episode.

Opportunities like that don’t come around very often, and I was determined that if I ever got another bite at the apple, I’d crunch.

Well, the gods of show business smiled on me, and I got my second chance.

Theresa Rebeck, one of Broadway’s most prolific and successful playwrights, wrote a pilot last year for NBC called “Smash.” It’s all about the insular, back-stabbing world of Broadway. A source slipped me Rebeck’s script, and I chuckled when I came across these lines:

“Riedel’s going to destroy us.”

“Why? Who is he?”

“He’s a Napoleonic little Nazi who writes for The Post. You don’t know who Michael Riedel is?”

“No.”

“You’re fired.”

I threw that into the column and got an e-mail from Rebeck saying she hoped I was not offended.

Of course not. I attack people all the time, so it’s only fair that the tables are (occasionally) turned on me. I jokingly suggested that I should make a cameo in a future episode should the pilot get picked up.

It did — and Rebeck called. “Would you really consider playing yourself?” she asked.

Oh, twist my arm if you must, but YOU’RE DAMN RIGHT I WOULD!

A few days before the shoot, the production office sent over my “sides.” (That’s what we television actors call the script.) I can’t say I had many “sides.” Two pages, in fact. Total number of lines: eight. But I was determined to make every one count. And, besides, my scene was with Anjelica Huston, who’s playing a Broadway producer in “Smash.”

I rehearsed day and night, throwing myself into, well, myself, as if I’d been created by Eugene O’Neill.

The scene was to be shot on location at a restaurant on the Upper East Side. In the scene, I walk into the restaurant and spy Anjelica having dinner with Doug Hughes, the real-life Broadway director. I sense they’re up to something, so I hop over to their table to find out.

My opening line was: “Hello, hello!” I delivered it with such panache that I have a hunch it’s going to become a national catchphrase.

“I could’ve had a V8.” “I’ve fallen and I can’t get up!” “Hello, hello!”

The restaurant was packed with extras pretending to have dinner. Extras rarely mix with principals (that is, those of us who have lines). And when we finished our scene, Anjelica, Doug and I were escorted to a private nook, where we were offered refreshments. The extras were herded to the back of the bar.

I felt sorry for them. Well, not really. The refreshments we “principals” were offered — fresh-cut fruit, bottled water, a catered Mexican lunch (vegetarian, if you wanted) — were wonderful.

We shot the scene five or six times and the director said, “OK, we got it.” I thought I was through, so I started to leave the restaurant, my Cinderella days over, my pumpkin days about to begin again. But my minder came after me. “We’re not done yet. We have to shoot it from other angles.”

Who knew?

And shoot it we did — from five different angles for the next four hours. But I was having fun. Maybe a little too much fun. By the end, my “Hello, hello!” had become a “H-E-L-L-L-O! H-E-L-L-L-LO!!” And I was holding Anjelica and Doug’s hands and saying, with a leer, “What are you two conspiring about?”

After our final take, Paul McGuigan, our director, said, “Thank you, ladies and gentleman. Good work today.” He turned to me and said, “And that’s it for you. You’ve become a ham.”

“Smash,” which debuts tomorrow night, is being hyped to the gills by NBC. But is middle American going to care about a TV series about theater people? Most shows set in New York are about cops and crime. “Smash” is about a bunch of insular eccentrics who think about one thing and one thing only — the theater and their place in it.

The challenge for Rebeck and her team will be to make these characters human and engaging. Theater people can be ambitious, back-stabbing and grandiose. But they’re also passionate, talented, insecure, very funny and willing to risk everything — money, reputation, years of their lives — on the one thing they love most — putting on a show.

The first episode has their number. If “Smash” can sustain that tone, then it could turn America into a nation of people who want nothing else but to be in show business.